Distribution And Rates Of Nitrogen Fixation In The Western Tropical South Pacific Ocean Constrained By Nitrogen Isotope Budgets
Constraining the rates and spatial distribution of dinitrogen (N-2) fixation fluxes to the ocean informs our understanding of the environmental sensitivities of N-2 fixation as well as the timescale over which the fluxes of nitrogen (N) to and from the ocean may respond to each other. Here we quanti...
Published in: | Biogeosciences |
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Other Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-15-2619-2018 http://purl.flvc.org/fsu/fd/FSU_libsubv1_wos_000431435900003 http://fsu.digital.flvc.org/islandora/object/fsu%3A606078/datastream/TN/view/Distribution%20And%20Rates%20Of%20Nitrogen%20Fixation%20In%20The%20Western%20Tropical%20South%20Pacific%20Ocean%20Constrained%20By%20Nitrogen%20Isotope%20Budgets.jpg |
Summary: | Constraining the rates and spatial distribution of dinitrogen (N-2) fixation fluxes to the ocean informs our understanding of the environmental sensitivities of N-2 fixation as well as the timescale over which the fluxes of nitrogen (N) to and from the ocean may respond to each other. Here we quantify rates of N-2 fixation as well as its contribution to export production along a zonal transect in the western tropical South Pacific (WTSP) Ocean using N isotope ("delta N-15") budgets. Comparing measurements of water column nitrate + nitrite delta N-15 with the delta N-15 of sinking particulate N at a western, central, and eastern station, these delta N-15 budgets indicate high, modest, and low rates of N-2 fixation at the respective stations. The results also imply that N-2 fixation supports exceptionally high, i.e. >= 50 %, of export production at the western and central stations, which are also proximal to the largest iron sources. These geochemically based rates of N-2 fixation are equal to or greater than those previously reported in the tropical North Atlantic, indicating that the WTSP Ocean has the capacity to support globally significant rates of N-2 fixation, which may compensate for N removal in the oxygen-deficient zones of the eastern tropical Pacific. fresh-water, n-2 fixation, nitrate, north pacific, iron availability, trichodesmium, export production, global distribution, new-caledonia, phosphate availability The publisher’s version of record is available at https://doi.org/10.5194/bg-15-2619-2018 |
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